Comprehensive on-line RPLC-CZE-MS of peptides

Peptide standards and tryptic digests of ribonuclease B are separated by comprehensive two-dimensional reversed phase liquid chromatography (RPLC) and capillary zone electrophoresis (CZE) and detected on-line by electrospray mass spectrometry. The RPLC column is coupled to the CZE column by a transverse flow gating interface. A new rugged microelectrospray needle is described that combines high ionization efficiency, low flow rates, and a sheath flow. The result is a system combining the separation capabilities of both RPLC and CZE with on-line mass spectrometric detection, all in about 15 min.